xref: /netbsd-src/sys/arch/hp300/dev/mt.c (revision 8ac07aec990b9d2e483062509d0a9fa5b4f57cf2)
1 /*	$NetBSD: mt.c,v 1.42 2008/03/29 06:47:08 tsutsui Exp $	*/
2 
3 /*-
4  * Copyright (c) 1996, 1997 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the NetBSD
21  *	Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Copyright (c) 1992, The University of Utah and
41  * the Computer Systems Laboratory at the University of Utah (CSL).
42  * All rights reserved.
43  *
44  * Permission to use, copy, modify and distribute this software is hereby
45  * granted provided that (1) source code retains these copyright, permission,
46  * and disclaimer notices, and (2) redistributions including binaries
47  * reproduce the notices in supporting documentation, and (3) all advertising
48  * materials mentioning features or use of this software display the following
49  * acknowledgement: ``This product includes software developed by the
50  * Computer Systems Laboratory at the University of Utah.''
51  *
52  * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
53  * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
54  * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
55  *
56  * CSL requests users of this software to return to csl-dist@cs.utah.edu any
57  * improvements that they make and grant CSL redistribution rights.
58  *
59  *	Utah $Hdr: mt.c 1.8 95/09/12$
60  */
61 /*	@(#)mt.c	3.9	90/07/10	mt Xinu
62  *
63  * Magnetic tape driver (7974a, 7978a/b, 7979a, 7980a, 7980xc)
64  * Original version contributed by Mt. Xinu.
65  * Modified for 4.4BSD by Mark Davies and Andrew Vignaux, Department of
66  * Computer Science, Victoria University of Wellington
67  */
68 
69 #include <sys/cdefs.h>
70 __KERNEL_RCSID(0, "$NetBSD: mt.c,v 1.42 2008/03/29 06:47:08 tsutsui Exp $");
71 
72 #include <sys/param.h>
73 #include <sys/systm.h>
74 #include <sys/callout.h>
75 #include <sys/buf.h>
76 #include <sys/bufq.h>
77 #include <sys/ioctl.h>
78 #include <sys/mtio.h>
79 #include <sys/file.h>
80 #include <sys/proc.h>
81 #include <sys/errno.h>
82 #include <sys/syslog.h>
83 #include <sys/tty.h>
84 #include <sys/kernel.h>
85 #include <sys/tprintf.h>
86 #include <sys/device.h>
87 #include <sys/conf.h>
88 
89 #include <hp300/dev/hpibvar.h>
90 
91 #include <hp300/dev/mtreg.h>
92 
93 #include "ioconf.h"
94 
95 static const struct mtinfo {
96 	u_short	hwid;
97 	const char *desc;
98 } mtinfo[] = {
99 	{ MT7978ID,	"7978"	},
100 	{ MT7979AID,	"7979A"	},
101 	{ MT7980ID,	"7980"	},
102 	{ MT7974AID,	"7974A"	},
103 };
104 static const int nmtinfo = sizeof(mtinfo) / sizeof(mtinfo[0]);
105 
106 struct	mt_softc {
107 	device_t sc_dev;
108 	struct	callout sc_start_ch;
109 	struct	callout sc_intr_ch;
110 	int	sc_hpibno;	/* logical HPIB this slave it attached to */
111 	int	sc_slave;	/* HPIB slave address (0-6) */
112 	short	sc_flags;	/* see below */
113 	u_char	sc_lastdsj;	/* place for DSJ in mtreaddsj() */
114 	u_char	sc_lastecmd;	/* place for End Command in mtreaddsj() */
115 	short	sc_recvtimeo;	/* count of hpibsend timeouts to prevent hang */
116 	short	sc_statindex;	/* index for next sc_stat when MTF_STATTIMEO */
117 	struct	mt_stat sc_stat;/* status bytes last read from device */
118 	short	sc_density;	/* current density of tape (mtio.h format) */
119 	short	sc_type;	/* tape drive model (hardware IDs) */
120 	struct	hpibqueue sc_hq; /* HPIB device queue member */
121 	tpr_t	sc_ttyp;
122 	struct bufq_state *sc_tab;/* buf queue */
123 	int	sc_active;
124 	struct buf sc_bufstore;	/* XXX buffer storage */
125 };
126 
127 #ifdef DEBUG
128 int	mtdebug = 0;
129 #define	dlog	if (mtdebug) log
130 #else
131 #define	dlog	if (0) log
132 #endif
133 
134 #define	UNIT(x)		(minor(x) & 3)
135 
136 #define B_CMD		B_DEVPRIVATE	/* command buf instead of data */
137 #define	b_cmd		b_blkno		/* blkno holds cmd when B_CMD */
138 
139 static int	mtmatch(device_t, cfdata_t, void *);
140 static void	mtattach(device_t, device_t, void *);
141 
142 CFATTACH_DECL_NEW(mt, sizeof(struct mt_softc),
143     mtmatch, mtattach, NULL, NULL);
144 
145 static dev_type_open(mtopen);
146 static dev_type_close(mtclose);
147 static dev_type_read(mtread);
148 static dev_type_write(mtwrite);
149 static dev_type_ioctl(mtioctl);
150 static dev_type_strategy(mtstrategy);
151 
152 const struct bdevsw mt_bdevsw = {
153 	mtopen, mtclose, mtstrategy, mtioctl, nodump, nosize, D_TAPE
154 };
155 
156 const struct cdevsw mt_cdevsw = {
157 	mtopen, mtclose, mtread, mtwrite, mtioctl,
158 	nostop, notty, nopoll, nommap, nokqfilter, D_TAPE
159 };
160 
161 static int	mtident(struct mt_softc *, struct hpibbus_attach_args *);
162 static void	mtustart(struct mt_softc *);
163 static int	mtreaddsj(struct mt_softc *, int);
164 static int	mtcommand(dev_t, int, int);
165 static void	spl_mtintr(void *);
166 static void	spl_mtstart(void *);
167 
168 static void	mtstart(void *);
169 static void	mtgo(void *);
170 static void	mtintr(void *);
171 
172 static int
173 mtmatch(device_t parent, cfdata_t cf, void *aux)
174 {
175 	struct hpibbus_attach_args *ha = aux;
176 
177 	return mtident(NULL, ha);
178 }
179 
180 static void
181 mtattach(device_t parent, device_t self, void *aux)
182 {
183 	struct mt_softc *sc = device_private(self);
184 	struct hpibbus_attach_args *ha = aux;
185 	int unit, hpibno, slave;
186 
187 	sc->sc_dev = self;
188 	if (mtident(sc, ha) == 0) {
189 		aprint_error(": impossible!\n");
190 		return;
191 	}
192 
193 	unit = device_unit(self);
194 	hpibno = device_unit(parent);
195 	slave = ha->ha_slave;
196 
197 	bufq_alloc(&sc->sc_tab, "fcfs", 0);
198 	callout_init(&sc->sc_start_ch, 0);
199 	callout_init(&sc->sc_intr_ch, 0);
200 
201 	sc->sc_hpibno = hpibno;
202 	sc->sc_slave = slave;
203 	sc->sc_flags = MTF_EXISTS;
204 
205 	/* Initialize hpib job queue entry. */
206 	sc->sc_hq.hq_softc = sc;
207 	sc->sc_hq.hq_slave = sc->sc_slave;
208 	sc->sc_hq.hq_start = mtstart;
209 	sc->sc_hq.hq_go = mtgo;
210 	sc->sc_hq.hq_intr = mtintr;
211 }
212 
213 static int
214 mtident(struct mt_softc *sc, struct hpibbus_attach_args *ha)
215 {
216 	int i;
217 
218 	for (i = 0; i < nmtinfo; i++) {
219 		if (ha->ha_id == mtinfo[i].hwid) {
220 			if (sc != NULL) {
221 				sc->sc_type = mtinfo[i].hwid;
222 				aprint_normal(": %s tape\n", mtinfo[i].desc);
223 			}
224 			return 1;
225 		}
226 	}
227 	return 0;
228 }
229 
230 /*
231  * Perform a read of "Device Status Jump" register and update the
232  * status if necessary.  If status is read, the given "ecmd" is also
233  * performed, unless "ecmd" is zero.  Returns DSJ value, -1 on failure
234  * and -2 on "temporary" failure.
235  */
236 static int
237 mtreaddsj(struct mt_softc *sc, int ecmd)
238 {
239 	int retval;
240 
241 	if (sc->sc_flags & MTF_STATTIMEO)
242 		goto getstats;
243 	retval = hpibrecv(sc->sc_hpibno,
244 	    (sc->sc_flags & MTF_DSJTIMEO) ? -1 : sc->sc_slave,
245 	    MTT_DSJ, &(sc->sc_lastdsj), 1);
246 	sc->sc_flags &= ~MTF_DSJTIMEO;
247 	if (retval != 1) {
248 		dlog(LOG_DEBUG, "%s can't hpibrecv DSJ",
249 		    device_xname(sc->sc_dev));
250 		if (sc->sc_recvtimeo == 0)
251 			sc->sc_recvtimeo = hz;
252 		if (--sc->sc_recvtimeo == 0)
253 			return -1;
254 		if (retval == 0)
255 			sc->sc_flags |= MTF_DSJTIMEO;
256 		return -2;
257 	}
258 	sc->sc_recvtimeo = 0;
259 	sc->sc_statindex = 0;
260 	dlog(LOG_DEBUG, "%s readdsj: 0x%x", device_xname(sc->sc_dev),
261 	    sc->sc_lastdsj);
262 	sc->sc_lastecmd = ecmd;
263 	switch (sc->sc_lastdsj) {
264 	    case 0:
265 		if (ecmd & MTE_DSJ_FORCE)
266 			break;
267 		return 0;
268 
269 	    case 2:
270 		sc->sc_lastecmd = MTE_COMPLETE;
271 	    case 1:
272 		break;
273 
274 	    default:
275 		log(LOG_ERR, "%s readdsj: DSJ 0x%x\n", device_xname(sc->sc_dev),
276 		    sc->sc_lastdsj);
277 		return -1;
278 	}
279  getstats:
280 	retval = hpibrecv(sc->sc_hpibno,
281 	    (sc->sc_flags & MTF_STATCONT) ? -1 : sc->sc_slave,
282 	    MTT_STAT, ((char *)&(sc->sc_stat)) + sc->sc_statindex,
283 	    sizeof(sc->sc_stat) - sc->sc_statindex);
284 	sc->sc_flags &= ~(MTF_STATTIMEO | MTF_STATCONT);
285 	if (retval != sizeof(sc->sc_stat) - sc->sc_statindex) {
286 		if (sc->sc_recvtimeo == 0)
287 			sc->sc_recvtimeo = hz;
288 		if (--sc->sc_recvtimeo != 0) {
289 			if (retval >= 0) {
290 				sc->sc_statindex += retval;
291 				sc->sc_flags |= MTF_STATCONT;
292 			}
293 			sc->sc_flags |= MTF_STATTIMEO;
294 			return -2;
295 		}
296 		log(LOG_ERR, "%s readdsj: can't read status",
297 		    device_xname(sc->sc_dev));
298 		return -1;
299 	}
300 	sc->sc_recvtimeo = 0;
301 	sc->sc_statindex = 0;
302 	dlog(LOG_DEBUG, "%s readdsj: status is %x %x %x %x %x %x",
303 	    device_xname(sc->sc_dev),
304 	    sc->sc_stat1, sc->sc_stat2, sc->sc_stat3,
305 	    sc->sc_stat4, sc->sc_stat5, sc->sc_stat6);
306 	if (sc->sc_lastecmd)
307 		(void) hpibsend(sc->sc_hpibno, sc->sc_slave,
308 		    MTL_ECMD, &(sc->sc_lastecmd), 1);
309 	return (int)sc->sc_lastdsj;
310 }
311 
312 static int
313 mtopen(dev_t dev, int flag, int mode, struct lwp *l)
314 {
315 	int unit = UNIT(dev);
316 	struct mt_softc *sc;
317 	int req_den;
318 	int error;
319 
320 	if (unit >= mt_cd.cd_ndevs ||
321 	    (sc = device_private(mt_cd.cd_devs[unit])) == NULL ||
322 	    (sc->sc_flags & MTF_EXISTS) == 0)
323 		return ENXIO;
324 
325 	dlog(LOG_DEBUG, "%s open: flags 0x%x", device_xname(sc->sc_dev),
326 	    sc->sc_flags);
327 	if (sc->sc_flags & MTF_OPEN)
328 		return EBUSY;
329 	sc->sc_flags |= MTF_OPEN;
330 	sc->sc_ttyp = tprintf_open(l->l_proc);
331 	if ((sc->sc_flags & MTF_ALIVE) == 0) {
332 		error = mtcommand(dev, MTRESET, 0);
333 		if (error != 0 || (sc->sc_flags & MTF_ALIVE) == 0)
334 			goto errout;
335 		if ((sc->sc_stat1 & (SR1_BOT | SR1_ONLINE)) == SR1_ONLINE)
336 			(void) mtcommand(dev, MTREW, 0);
337 	}
338 	for (;;) {
339 		if ((error = mtcommand(dev, MTNOP, 0)) != 0)
340 			goto errout;
341 		if (!(sc->sc_flags & MTF_REW))
342 			break;
343 		if (tsleep((void *) &lbolt, PCATCH | (PZERO + 1),
344 		    "mt", 0) != 0) {
345 			error = EINTR;
346 			goto errout;
347 		}
348 	}
349 	if ((flag & FWRITE) && (sc->sc_stat1 & SR1_RO)) {
350 		error = EROFS;
351 		goto errout;
352 	}
353 	if (!(sc->sc_stat1 & SR1_ONLINE)) {
354 		uprintf("%s: not online\n", device_xname(sc->sc_dev));
355 		error = EIO;
356 		goto errout;
357 	}
358 	/*
359 	 * Select density:
360 	 *  - find out what density the drive is set to
361 	 *	(i.e. the density of the current tape)
362 	 *  - if we are going to write
363 	 *    - if we're not at the beginning of the tape
364 	 *      - complain if we want to change densities
365 	 *    - otherwise, select the mtcommand to set the density
366 	 *
367 	 * If the drive doesn't support it then don't change the recorded
368 	 * density.
369 	 *
370 	 * The original MOREbsd code had these additional conditions
371 	 * for the mid-tape change
372 	 *
373 	 *	req_den != T_BADBPI &&
374 	 *	sc->sc_density != T_6250BPI
375 	 *
376 	 * which suggests that it would be possible to write multiple
377 	 * densities if req_den == T_BAD_BPI or the current tape
378 	 * density was 6250.  Testing of our 7980 suggests that the
379 	 * device cannot change densities mid-tape.
380 	 *
381 	 * ajv@comp.vuw.ac.nz
382 	 */
383 	sc->sc_density = (sc->sc_stat2 & SR2_6250) ? T_6250BPI : (
384 			 (sc->sc_stat3 & SR3_1600) ? T_1600BPI : (
385 			 (sc->sc_stat3 & SR3_800) ? T_800BPI : -1));
386 	req_den = (dev & T_DENSEL);
387 
388 	if (flag & FWRITE) {
389 		if (!(sc->sc_stat1 & SR1_BOT)) {
390 			if (sc->sc_density != req_den) {
391 				uprintf("%s: can't change density mid-tape\n",
392 				    device_xname(sc->sc_dev));
393 				error = EIO;
394 				goto errout;
395 			}
396 		}
397 		else {
398 			int mtset_density =
399 			    (req_den == T_800BPI  ? MTSET800BPI : (
400 			     req_den == T_1600BPI ? MTSET1600BPI : (
401 			     req_den == T_6250BPI ? MTSET6250BPI : (
402 			     sc->sc_type == MT7980ID
403 						  ? MTSET6250DC
404 						  : MTSET6250BPI))));
405 			if (mtcommand(dev, mtset_density, 0) == 0)
406 				sc->sc_density = req_den;
407 		}
408 	}
409 	return 0;
410 errout:
411 	sc->sc_flags &= ~MTF_OPEN;
412 	return error;
413 }
414 
415 static int
416 mtclose(dev_t dev, int flag, int fmt, struct lwp *l)
417 {
418 	struct mt_softc *sc = device_private(mt_cd.cd_devs[UNIT(dev)]);
419 
420 	if (sc->sc_flags & MTF_WRT) {
421 		(void) mtcommand(dev, MTWEOF, 2);
422 		(void) mtcommand(dev, MTBSF, 0);
423 	}
424 	if ((minor(dev) & T_NOREWIND) == 0)
425 		(void) mtcommand(dev, MTREW, 0);
426 	sc->sc_flags &= ~MTF_OPEN;
427 	tprintf_close(sc->sc_ttyp);
428 	return 0;
429 }
430 
431 static int
432 mtcommand(dev_t dev, int cmd, int cnt)
433 {
434 	struct mt_softc *sc = device_private(mt_cd.cd_devs[UNIT(dev)]);
435 	struct buf *bp = &sc->sc_bufstore;
436 	int error = 0;
437 
438 #if 1
439 	if (bp->b_cflags & BC_BUSY)
440 		return EBUSY;
441 #endif
442 	bp->b_cmd = cmd;
443 	bp->b_dev = dev;
444 	do {
445 		bp->b_cflags = BC_BUSY;
446 		bp->b_flags = B_CMD;
447 		mtstrategy(bp);
448 		biowait(bp);
449 		if (bp->b_error != 0) {
450 			error = bp->b_error;
451 			break;
452 		}
453 	} while (--cnt > 0);
454 #if 0
455 	bp->b_flags = 0 /*&= ~BC_BUSY*/;
456 #else
457 	bp->b_flags &= ~BC_BUSY;
458 #endif
459 	return error;
460 }
461 
462 /*
463  * Only thing to check here is for legal record lengths (writes only).
464  */
465 static void
466 mtstrategy(struct buf *bp)
467 {
468 	struct mt_softc *sc;
469 	int unit;
470 	int s;
471 
472 	unit = UNIT(bp->b_dev);
473 	sc = device_private(mt_cd.cd_devs[unit]);
474 	dlog(LOG_DEBUG, "%s strategy", device_xname(sc->sc_dev));
475 	if ((bp->b_flags & (B_CMD | B_READ)) == 0) {
476 #define WRITE_BITS_IGNORED	8
477 #if 0
478 		if (bp->b_bcount & ((1 << WRITE_BITS_IGNORED) - 1)) {
479 			tprintf(sc->sc_ttyp,
480 			    "%s: write record must be multiple of %d\n",
481 			    device_xname(sc->sc_dev), 1 << WRITE_BITS_IGNORED);
482 			goto error;
483 		}
484 #endif
485 		s = 16 * 1024;
486 		if (sc->sc_stat2 & SR2_LONGREC) {
487 			switch (sc->sc_density) {
488 			    case T_1600BPI:
489 				s = 32 * 1024;
490 				break;
491 
492 			    case T_6250BPI:
493 			    case T_BADBPI:
494 				s = 60 * 1024;
495 				break;
496 			}
497 		}
498 		if (bp->b_bcount > s) {
499 			tprintf(sc->sc_ttyp,
500 			    "%s: write record (%d) too big: limit (%d)\n",
501 			    device_xname(sc->sc_dev), bp->b_bcount, s);
502 #if 0 /* XXX see above */
503 	    error:
504 #endif
505 			bp->b_error = EIO;
506 			biodone(bp);
507 			return;
508 		}
509 	}
510 	s = splbio();
511 	BUFQ_PUT(sc->sc_tab, bp);
512 	if (sc->sc_active == 0) {
513 		sc->sc_active = 1;
514 		mtustart(sc);
515 	}
516 	splx(s);
517 }
518 
519 static void
520 mtustart(struct mt_softc *sc)
521 {
522 
523 	dlog(LOG_DEBUG, "%s ustart", device_xname(sc->sc_dev));
524 	if (hpibreq(device_parent(sc->sc_dev), &sc->sc_hq))
525 		mtstart(sc);
526 }
527 
528 static void
529 spl_mtintr(void *arg)
530 {
531 	struct mt_softc *sc = arg;
532 	int s = splbio();
533 
534 	hpibppclear(sc->sc_hpibno);
535 	mtintr(sc);
536 	splx(s);
537 }
538 
539 static void
540 spl_mtstart(void *arg)
541 {
542 	int s = splbio();
543 
544 	mtstart(arg);
545 	splx(s);
546 }
547 
548 static void
549 mtstart(void *arg)
550 {
551 	struct mt_softc *sc = arg;
552 	struct buf *bp;
553 	short	cmdcount = 1;
554 	u_char	cmdbuf[2];
555 
556 	dlog(LOG_DEBUG, "%s start", device_xname(sc->sc_dev));
557 	sc->sc_flags &= ~MTF_WRT;
558 	bp = BUFQ_PEEK(sc->sc_tab);
559 	if ((sc->sc_flags & MTF_ALIVE) == 0 &&
560 	    ((bp->b_flags & B_CMD) == 0 || bp->b_cmd != MTRESET))
561 		goto fatalerror;
562 
563 	if (sc->sc_flags & MTF_REW) {
564 		if (!hpibpptest(sc->sc_hpibno, sc->sc_slave))
565 			goto stillrew;
566 		switch (mtreaddsj(sc, MTE_DSJ_FORCE|MTE_COMPLETE|MTE_IDLE)) {
567 		    case 0:
568 		    case 1:
569 		stillrew:
570 			if ((sc->sc_stat1 & SR1_BOT) ||
571 			    !(sc->sc_stat1 & SR1_ONLINE)) {
572 				sc->sc_flags &= ~MTF_REW;
573 				break;
574 			}
575 		    case -2:
576 			/*
577 			 * -2 means "timeout" reading DSJ, which is probably
578 			 * temporary.  This is considered OK when doing a NOP,
579 			 * but not otherwise.
580 			 */
581 			if (sc->sc_flags & (MTF_DSJTIMEO | MTF_STATTIMEO)) {
582 				callout_reset(&sc->sc_start_ch, hz >> 5,
583 				    spl_mtstart, sc);
584 				return;
585 			}
586 		    case 2:
587 			if (bp->b_cmd != MTNOP || !(bp->b_flags & B_CMD)) {
588 				bp->b_error = EBUSY;
589 				goto done;
590 			}
591 			goto done;
592 
593 		    default:
594 			goto fatalerror;
595 		}
596 	}
597 	if (bp->b_flags & B_CMD) {
598 		if (sc->sc_flags & MTF_PASTEOT) {
599 			switch(bp->b_cmd) {
600 			    case MTFSF:
601 			    case MTWEOF:
602 			    case MTFSR:
603 				bp->b_error = ENOSPC;
604 				goto done;
605 
606 			    case MTBSF:
607 			    case MTOFFL:
608 			    case MTBSR:
609 			    case MTREW:
610 				sc->sc_flags &= ~(MTF_PASTEOT | MTF_ATEOT);
611 				break;
612 			}
613 		}
614 		switch(bp->b_cmd) {
615 		    case MTFSF:
616 			if (sc->sc_flags & MTF_HITEOF)
617 				goto done;
618 			cmdbuf[0] = MTTC_FSF;
619 			break;
620 
621 		    case MTBSF:
622 			if (sc->sc_flags & MTF_HITBOF)
623 				goto done;
624 			cmdbuf[0] = MTTC_BSF;
625 			break;
626 
627 		    case MTOFFL:
628 			sc->sc_flags |= MTF_REW;
629 			cmdbuf[0] = MTTC_REWOFF;
630 			break;
631 
632 		    case MTWEOF:
633 			cmdbuf[0] = MTTC_WFM;
634 			break;
635 
636 		    case MTBSR:
637 			cmdbuf[0] = MTTC_BSR;
638 			break;
639 
640 		    case MTFSR:
641 			cmdbuf[0] = MTTC_FSR;
642 			break;
643 
644 		    case MTREW:
645 			sc->sc_flags |= MTF_REW;
646 			cmdbuf[0] = MTTC_REW;
647 			break;
648 
649 		    case MTNOP:
650 			/*
651 			 * NOP is supposed to set status bits.
652 			 * Force readdsj to do it.
653 			 */
654 			switch (mtreaddsj(sc,
655 			  MTE_DSJ_FORCE | MTE_COMPLETE | MTE_IDLE)) {
656 			    default:
657 				goto done;
658 
659 			    case -1:
660 				/*
661 				 * If this fails, perform a device clear
662 				 * to fix any protocol problems and (most
663 				 * likely) get the status.
664 				 */
665 				bp->b_cmd = MTRESET;
666 				break;
667 
668 			    case -2:
669 				callout_reset(&sc->sc_start_ch, hz >> 5,
670 				    spl_mtstart, sc);
671 				return;
672 			}
673 
674 		    case MTRESET:
675 			/*
676 			 * 1) selected device clear (send with "-2" secondary)
677 			 * 2) set timeout, then wait for "service request"
678 			 * 3) interrupt will read DSJ (and END COMPLETE-IDLE)
679 			 */
680 			if (hpibsend(sc->sc_hpibno, sc->sc_slave, -2, NULL, 0)){
681 				log(LOG_ERR, "%s can't reset",
682 				    device_xname(sc->sc_dev));
683 				goto fatalerror;
684 			}
685 			callout_reset(&sc->sc_intr_ch, 4 * hz, spl_mtintr, sc);
686 			hpibawait(sc->sc_hpibno);
687 			return;
688 
689 		    case MTSET800BPI:
690 			cmdbuf[0] = MTTC_800;
691 			break;
692 
693 		    case MTSET1600BPI:
694 			cmdbuf[0] = MTTC_1600;
695 			break;
696 
697 		    case MTSET6250BPI:
698 			cmdbuf[0] = MTTC_6250;
699 			break;
700 
701 		    case MTSET6250DC:
702 			cmdbuf[0] = MTTC_DC6250;
703 			break;
704 		}
705 	} else {
706 		if (sc->sc_flags & MTF_PASTEOT) {
707 			bp->b_error = ENOSPC;
708 			goto done;
709 		}
710 		if (bp->b_flags & B_READ) {
711 			sc->sc_flags |= MTF_IO;
712 			cmdbuf[0] = MTTC_READ;
713 		} else {
714 			sc->sc_flags |= MTF_WRT | MTF_IO;
715 			cmdbuf[0] = MTTC_WRITE;
716 			cmdbuf[1] = (bp->b_bcount + ((1 << WRITE_BITS_IGNORED) - 1)) >> WRITE_BITS_IGNORED;
717 			cmdcount = 2;
718 		}
719 	}
720 	if (hpibsend(sc->sc_hpibno, sc->sc_slave, MTL_TCMD, cmdbuf, cmdcount)
721 	    == cmdcount) {
722 		if (sc->sc_flags & MTF_REW)
723 			goto done;
724 		hpibawait(sc->sc_hpibno);
725 		return;
726 	}
727 fatalerror:
728 	/*
729 	 * If anything fails, the drive is probably hosed, so mark it not
730 	 * "ALIVE" (but it EXISTS and is OPEN or we wouldn't be here, and
731 	 * if, last we heard, it was REWinding, remember that).
732 	 */
733 	sc->sc_flags &= MTF_EXISTS | MTF_OPEN | MTF_REW;
734 	bp->b_error = EIO;
735 done:
736 	sc->sc_flags &= ~(MTF_HITEOF | MTF_HITBOF);
737 	(void)BUFQ_GET(sc->sc_tab);
738 	biodone(bp);
739 	hpibfree(device_parent(sc->sc_dev), &sc->sc_hq);
740 	if ((bp = BUFQ_PEEK(sc->sc_tab)) == NULL)
741 		sc->sc_active = 0;
742 	else
743 		mtustart(sc);
744 }
745 
746 /*
747  * The Utah code had a bug which meant that the driver was unable to read.
748  * "rw" was initialized to bp->b_flags & B_READ before "bp" was initialized.
749  *   -- ajv@comp.vuw.ac.nz
750  */
751 static void
752 mtgo(void *arg)
753 {
754 	struct mt_softc *sc = arg;
755 	struct buf *bp;
756 	int rw;
757 
758 	dlog(LOG_DEBUG, "%s go", device_xname(sc->sc_dev));
759 	bp = BUFQ_PEEK(sc->sc_tab);
760 	rw = bp->b_flags & B_READ;
761 	hpibgo(sc->sc_hpibno, sc->sc_slave, rw ? MTT_READ : MTL_WRITE,
762 	    bp->b_data, bp->b_bcount, rw, rw != 0);
763 }
764 
765 static void
766 mtintr(void *arg)
767 {
768 	struct mt_softc *sc = arg;
769 	struct buf *bp;
770 	int i;
771 	u_char cmdbuf[4];
772 
773 	bp = BUFQ_PEEK(sc->sc_tab);
774 	if (bp == NULL) {
775 		log(LOG_ERR, "%s intr: bp == NULL", device_xname(sc->sc_dev));
776 		return;
777 	}
778 
779 	dlog(LOG_DEBUG, "%s intr", device_xname(sc->sc_dev));
780 
781 	/*
782 	 * Some operation completed.  Read status bytes and report errors.
783 	 * Clear EOF flags here `cause they're set once on specific conditions
784 	 * below when a command succeeds.
785 	 * A DSJ of 2 always means keep waiting.  If the command was READ
786 	 * (and we're in data DMA phase) stop data transfer first.
787 	 */
788 	sc->sc_flags &= ~(MTF_HITEOF | MTF_HITBOF);
789 	if ((bp->b_flags & (B_CMD|B_READ)) == B_READ &&
790 	    !(sc->sc_flags & (MTF_IO | MTF_STATTIMEO | MTF_DSJTIMEO))){
791 		cmdbuf[0] = MTE_STOP;
792 		(void) hpibsend(sc->sc_hpibno, sc->sc_slave, MTL_ECMD,cmdbuf,1);
793 	}
794 	switch (mtreaddsj(sc, 0)) {
795 	    case 0:
796 		break;
797 
798 	    case 1:
799 		/*
800 		 * If we're in the middle of a READ/WRITE and have yet to
801 		 * start the data transfer, a DSJ of one should terminate it.
802 		 */
803 		sc->sc_flags &= ~MTF_IO;
804 		break;
805 
806 	    case 2:
807 		(void) hpibawait(sc->sc_hpibno);
808 		return;
809 
810 	    case -2:
811 		/*
812 		 * -2 means that the drive failed to respond quickly enough
813 		 * to the request for DSJ.  It's probably just "busy" figuring
814 		 * it out and will know in a little bit...
815 		 */
816 		callout_reset(&sc->sc_intr_ch, hz >> 5, spl_mtintr, sc);
817 		return;
818 
819 	    default:
820 		log(LOG_ERR, "%s intr: can't get drive stat",
821 		    device_xname(sc->sc_dev));
822 		goto error;
823 	}
824 	if (sc->sc_stat1 & (SR1_ERR | SR1_REJECT)) {
825 		i = sc->sc_stat4 & SR4_ERCLMASK;
826 		log(LOG_ERR, "%s: %s error, retry %d, SR2/3 %x/%x, code %d",
827 			device_xname(sc->sc_dev), i == SR4_DEVICE ? "device" :
828 			(i == SR4_PROTOCOL ? "protocol" :
829 			(i == SR4_SELFTEST ? "selftest" : "unknown")),
830 			sc->sc_stat4 & SR4_RETRYMASK, sc->sc_stat2,
831 			sc->sc_stat3, sc->sc_stat5);
832 
833 		if ((bp->b_flags & B_CMD) && bp->b_cmd == MTRESET)
834 			callout_stop(&sc->sc_intr_ch);
835 		if (sc->sc_stat3 & SR3_POWERUP)
836 			sc->sc_flags &= MTF_OPEN | MTF_EXISTS;
837 		goto error;
838 	}
839 	/*
840 	 * Report and clear any soft errors.
841 	 */
842 	if (sc->sc_stat1 & SR1_SOFTERR) {
843 		log(LOG_WARNING, "%s: soft error, retry %d\n",
844 		    device_xname(sc->sc_dev), sc->sc_stat4 & SR4_RETRYMASK);
845 		sc->sc_stat1 &= ~SR1_SOFTERR;
846 	}
847 	/*
848 	 * We've initiated a read or write, but haven't actually started to
849 	 * DMA the data yet.  At this point, the drive's ready.
850 	 */
851 	if (sc->sc_flags & MTF_IO) {
852 		sc->sc_flags &= ~MTF_IO;
853 		if (hpibustart(sc->sc_hpibno))
854 			mtgo(sc);
855 		return;
856 	}
857 	/*
858 	 * Check for End Of Tape - we're allowed to hit EOT and then write (or
859 	 * read) one more record.  If we get here and have not already hit EOT,
860 	 * return ENOSPC to inform the process that it's hit it.  If we get
861 	 * here and HAVE already hit EOT, don't allow any more operations that
862 	 * move the tape forward.
863 	 */
864 	if (sc->sc_stat1 & SR1_EOT) {
865 		if (sc->sc_flags & MTF_ATEOT)
866 			sc->sc_flags |= MTF_PASTEOT;
867 		else {
868 			bp->b_error = ENOSPC;
869 			sc->sc_flags |= MTF_ATEOT;
870 		}
871 	}
872 	/*
873 	 * If a motion command was being executed, check for Tape Marks.
874 	 * If we were doing data, make sure we got the right amount, and
875 	 * check for hitting tape marks on reads.
876 	 */
877 	if (bp->b_flags & B_CMD) {
878 		if (sc->sc_stat1 & SR1_EOF) {
879 			if (bp->b_cmd == MTFSR)
880 				sc->sc_flags |= MTF_HITEOF;
881 			if (bp->b_cmd == MTBSR)
882 				sc->sc_flags |= MTF_HITBOF;
883 		}
884 		if (bp->b_cmd == MTRESET) {
885 			callout_stop(&sc->sc_intr_ch);
886 			sc->sc_flags |= MTF_ALIVE;
887 		}
888 	} else {
889 		i = hpibrecv(sc->sc_hpibno, sc->sc_slave, MTT_BCNT, cmdbuf, 2);
890 		if (i != 2) {
891 			log(LOG_ERR, "%s intr: can't get xfer length\n",
892 			    device_xname(sc->sc_dev));
893 			goto error;
894 		}
895 		i = (int) *((u_short *) cmdbuf);
896 		if (i <= bp->b_bcount) {
897 			if (i == 0)
898 				sc->sc_flags |= MTF_HITEOF;
899 			bp->b_resid = bp->b_bcount - i;
900 			dlog(LOG_DEBUG, "%s intr: bcount %d, resid %d",
901 			    device_xname(sc->sc_dev), bp->b_bcount,
902 			    bp->b_resid);
903 		} else {
904 			tprintf(sc->sc_ttyp,
905 				"%s: record (%d) larger than wanted (%d)\n",
906 				device_xname(sc->sc_dev), i, bp->b_bcount);
907  error:
908 			sc->sc_flags &= ~MTF_IO;
909 			bp->b_error = EIO;
910 		}
911 	}
912 	/*
913 	 * The operation is completely done.
914 	 * Let the drive know with an END command.
915 	 */
916 	cmdbuf[0] = MTE_COMPLETE | MTE_IDLE;
917 	(void) hpibsend(sc->sc_hpibno, sc->sc_slave, MTL_ECMD, cmdbuf, 1);
918 	bp->b_flags &= ~B_CMD;
919 	(void)BUFQ_GET(sc->sc_tab);
920 	biodone(bp);
921 	hpibfree(device_parent(sc->sc_dev), &sc->sc_hq);
922 	if (BUFQ_PEEK(sc->sc_tab) == NULL)
923 		sc->sc_active = 0;
924 	else
925 		mtustart(sc);
926 }
927 
928 static int
929 mtread(dev_t dev, struct uio *uio, int flags)
930 {
931 	struct mt_softc *sc = device_private(mt_cd.cd_devs[UNIT(dev)]);
932 
933 	return physio(mtstrategy, &sc->sc_bufstore,
934 	    dev, B_READ, minphys, uio);
935 }
936 
937 static int
938 mtwrite(dev_t dev, struct uio *uio, int flags)
939 {
940 	struct mt_softc *sc = device_private(mt_cd.cd_devs[UNIT(dev)]);
941 
942 	return physio(mtstrategy, &sc->sc_bufstore,
943 	    dev, B_WRITE, minphys, uio);
944 }
945 
946 static int
947 mtioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
948 {
949 	struct mtop *op;
950 	int cnt;
951 
952 	switch (cmd) {
953 	    case MTIOCTOP:
954 		op = (struct mtop *)data;
955 		switch(op->mt_op) {
956 		    case MTWEOF:
957 		    case MTFSF:
958 		    case MTBSR:
959 		    case MTBSF:
960 		    case MTFSR:
961 			cnt = op->mt_count;
962 			break;
963 
964 		    case MTOFFL:
965 		    case MTREW:
966 		    case MTNOP:
967 			cnt = 0;
968 			break;
969 
970 		    default:
971 			return EINVAL;
972 		}
973 		return mtcommand(dev, op->mt_op, cnt);
974 
975 	    case MTIOCGET:
976 		break;
977 
978 	    default:
979 		return EINVAL;
980 	}
981 	return 0;
982 }
983